I just put an 998 on my rig it took about an hour to install; I got mine from Cabelas online and it came with the Navionics and they are great 1999$. I took it out today for the first time and I've never had a Di or Si unit and really I coun't be more satisfied I read the instructions once or twice before I got it (kid at Christmas time). It came with a CD that had all the installation instructions and the operators manual got confused installing it (was on the wrong page) called Humminbird and the lady was nice enough to tell me to scroll down and get on the correct transducer.:o The unit has a simulator feature that you can use where you run through all the operations and practice really helpfull and user friendly. I got the 998 because I fish CM and some of the fellas told me that Lorance had some problems and I would be happier with the 998 and I must say I am quite impressed not hard to use or install just make sure your boat is level as it would be in the water and your GOLD! Just my 2 cents good luck KYRich.